"The reptile will be humanely trapped and relocated to a zoo for veterinary evaluation," Chicago Police spokeswoman Kellie Bartoli told NPR in an email.

But in the meantime, the city and the wider world via social media are having a field day with the urban lurker. Thousands of people voted in a nicknaming competition; Chance the Snapper was the winner, beating out Ruth Gator Ginsburg and Croc Obama.

And a real-life neighborhood alligator wrangler, clad head to toe in khaki, has swooped in to help.

Known as Alligator Bob, he has been volunteering with the Chicago Herpetological Society for decades, the group's president, Rich Crowley, told NPR in a phone interview. But Alligator Bob has a day job and won't release his legal name in a bid to preserve his privacy.

Tracking down alligators in Chicago, which are not native to the area, is not as rare an occurrence as one might think.

"We probably get maybe a couple a year," Crowley said.

He is certain the alligator in Humboldt Park is an unwanted pet and suspects it was dumped recently because it had not been spotted before Tuesday in the heavily trafficked area.

Similar scenarios have played out many times before. People take on what they think of as an exotic pet when it is young and cute. But, of course, the animals grow and once owners find them to be too much trouble, "they typically dump them in parks and forest reserves," Crowley said.

In a bid to get the Humboldt Park alligator out of the water, several "safe" snares, designed not to injure the animal, have been baited with fish and chicken.

But the alligator could also be feeding on frogs, rodents and fish in and around the waterway.

Based on the alligator's smaller size, Crowley does not believe it would go after a human. People are nevertheless advised to keep out of the lagoon, because the gator could attack if it feels threatened.

Its instincts to stay away from people and its ability to blend in are making it harder to trap. "This is an animal well-suited with camouflage," Crowley said. "They're really good at evading capture."

As the alligator becomes more familiar with its habitat and hiding spots, outsmarting it could prove to be even trickier.

Crowley said with Chicago's temperature drop from the 90s earlier in the week to the 70s on Thursday, he is hopeful the alligator could facilitate its own capture. The cold-blooded creature could be enticed to emerge from the lagoon and bask on a hot rock.